In the book The Outsiders, what literary device does the author use to describe Johnny's mugging?
The sequence that you are asking about is from chapter 2. Ponyboy and Cherry are walking together and she asks about Johnny. She wants to know why she gets the vibe that "he's been hurt bad sometime." Ponyboy says that he doesn't like to talk about it, but he starts talking to Cherry fairly quickly in this case.
The first technique is flashback and Hinton tells her reader that the story is flashing back almost four months. Within the flashback are a few other literary devices. Foreshadowing for example occurs when Ponyboy and Steve find Johnny's only jacket. It has a rust colored stain on it, and there are more stains on the grass. Then there is a dehumanizing technique used when Johnny is first described as a "dark motionless hump."
Another example of foreshadowing is at the end of the flashback when it tells the reader that Johnny now carries a knife and has declared that he will kill the next person who jumps him like that.